The relationship between age, axial length and retinal nerve fiber layer thickness in the normal elderly population in Taiwan: The Chiayi eye study in Taiwan.

AIMS: To interpret how the thickness of the peripapillary retinal nerve fiber layer (RNFL) changes with increasing age, axial length, or anterior chamber depth as measured by spectral domain optical coherence tomography (OCT) in the normal elderly population in Taiwan. METHODS: A total of 82 volunteers (143 eyes) were enrolled. Generalized estimating equations were used to evaluate the correlation. RESULTS: The RNFL was significantly thinner in the superonasal (p = 0.004), inferotemporal (p = 0.046), and temporolower (p = 0.009) segments with age. The same trend was also observed in the superotemporal (p = 0.330) segment, although it was not statistically significant. The global RNFL thickness decreased by 4.97 µm per decade (ß = -0.497; p = 0.021), and thinning was significant in the superonasal (-9.90 µm per decade, p < 0.001) and temporolower (-6.78 µm per decade, p < 0.001) segments; the same trend showed borderline significance in the superotemporal (-6.96 µm per decade, p = 0.073) and inferotemporal (-7.23 µm per decade, p = 0.059) segments. In eyes with longer axial length, the RNFLs significantly decreased in the non-temporal segments. Global RNFL thickness decreased by 3.086 µm for each additional millimeter of axial length (ß = -3.086; p < 0.001). CONCLUSIONS: Changes in RNFL thickness were correlated with age in the superonasal, superotemporal, inferotemporal, and temporolower segments, and were correlated with axial length in the non-temporal segments. Anterior chamber depth was not correlated with RNFL thickness.

Axial length and subfoveal choroidal thickness in individuals with age-related macular degeneration.

PURPOSE: To compare axial length (AL) and subfoveal choroidal thickness (SFCT) between individuals with age-related macular degeneration (AMD) and controls with no lesions. METHODS: This was a case-control study. In total, 853 eyes of 484 patients (>65 years), including 397 eyes at various AMD stages and 456 eyes with no fundus lesions (controls) were recruited. Using color fundus photography, eyes were grouped according to AMD degree. AL was automatically measured using IOL Master and SFCT was manually measured by two independent observers. The associations among age, AL, SFCT, and each AMD grade were analyzed. RESULTS: Out of 853 eyes, 456 had no lesions, 217 contained drusen only, 134 had early AMD, and 46 had late AMD. The eyes with late AMD were older (p = 0.007) and had longer AL (p ≥ 0.001) and thinner SFCT (p < 0.001) compared with groups of no fundus lesions, drusen only, and early AMD. SFCT in eyes with late AMD decreased by 19.20 µm (p = 0.049), 24.78 µm (p = 0.029), and 15.56 µm (p = 0.162) compared with groups of no fundus lesions, drusen only, and early AMD, respectively. SFCT decreased by 14.18 µm/mm increase in AL (p < 0.001). The odds ratio (OR) for late AMD by longer AL (≥25 mm) and thinner SFCT (<240 µm) was 4.54 (χ2 = 9.36; p = 0.002) and 4.86 (χ2 = 17.62; p < 0.001), respectively, and was 9.57 (χ2 = 18.07; p < 0.001) when both AL ≥ 25 ≥m and SFCT < 240 µm. CONCLUSION: Eyes with late AMD have distinct reduced SFCT and elongated AL. Eyes with thinner SFCT and longer AL showed high ORs for late AMD and even higher ORs when both factors were simultaneously present. These findings illustrate the crucial pathophysiological role of these two important ocular fac tors and arouse our attention to patients with both characteristics, especially in Asian countries where the prevalence of myopia are disturbingly high.